Receiving arrangement for wireless telegraphy



May 17, I927.

A. MEISSNER RECEIVING ARRANGEMENT FOR WIRELESS TELEGRAPHY Filed Sept. 3. 1921 lvwe utoz ALEXANDER MEISSNER Patented May 17, 1927.

UNITED STATES PATENT OFFICE.

ALEXANDER MEISSNEB, OF 3W, GEEMANE, .:ASSIGNOB D0 GESELIJSCHALFT TELEGRAEEIHME M. B. H., OlF BERLIN. JGEWANY, A OORPQRATIOIN GI GmHWNY.

RECEIVING ARBANGEMEN T FOR WIRELESS TELEGRAPHY.

Application filed September 3, 1821, Serial No. 498,417, and in Germany March 6, 1917.

(GRANTED UNUER THE PROVISIONS OF THE ACT 01" MARCH 3, 1921, 41 STAT. L., 1318.)

The present invention relates to a receiving arrangement for wireless telegraphy and antenna branch is tuned to the wave which it is desired to receive, Whereas, the other antenna or other branch has a different 111(11- vidual oscillating period, and a detector circuit is usually placed in con'ipensating con nection with the parts of the receiving system, the disturbing energies transmitted from both parts of the receiving system being made equal so liar as possible, and of opposite phase and.the signalling energies being unequal, so that the detector is actuated only by the signaling energy.

Such arrangements give satisfactory results when it is desired to eliminate disturhances by a .loreign wave, because in this case the distrirrbing energies have the same eriodicity and approximately equal energy m both parts of the receiving system. However, the elimination of atmospheric disturbances is only partially accomplished by the arrangements. 'ilwo entirely separate antennae are not energized with the same strength in response to all atmospheric disturbances, because of diflerences in the direction, capacity, resprmsiveness, etc. Moreover, infthe case oi an "atmospheric impulse, di fieren't branches of an antenna receive "most waves at different strengths and for this reason complete compensation cannot be cfleded. Finally, high frequency compensation such as is attempted "to be effected in known arrangements can not give satisfactory results, because the disturbing energy is transmitted to the detector circuit in waves of difl'crcnt lengths, it being; understood that high fre nency compensation of two "waves is possib e only when the waves have "the same amplitude and are of equal wave lengths and opposite phase.

In accordance with the present invention, these drawbacks are eliminated by an arrangement including a single antenna tuned to two Wave lengths, one of which is the wave length oflhe energy which his desired to receive. Instead of attempting immedilengths. The secondary circuits are loosely coupled with the antenna. In this manner the energy received from space is entirel separated in the sectmdary circuits, one of them receiving only disturbing ener and the other both signalling and disturbing energy. Due to such separation of the energy, the disturbing energy can be completely cempensated, since the respective portions of said energy in the secondary circuits may be easily equalized. In order to ell ect the compel'isation, according to the present invention. the portions of the disturbing energy in the secondary circuits are rectified by means of separate detectors and are transmitted into a low frequency circuit contain ing a common indicating apparatus. Thus, compensation is eflected at low f requcncy' and imle 'iendently of differentwave lengths of the high frequency snort, Finally, in accordance with the invention, detectors of substantially identical characteristics are used so as to cause equal disturbing energies to be transmitted by the detectors to the low frequency circuit. In previously known arrangenlenrts this has not been sufliciently taken into account. Entirely satisfactory results can be attained if a so-callcd audion is used as a detector.

The drawing, represents in Figs. 1 and 2 circuit arrangements of difiermrt forms cmbodying the invention.

Fig. 1 shows acircuit arrangement for receiving modulated Waves from tone senders. The antenna 1 is tuned to two wave lengths by means of a circuit 2 permanentlycoupled therewith, one of said Wave lengths being that of the signals to be received. The an tenna transmits signalling energy and disturbances to a secondary circuit 3 also tuned to the signals. Disturbances are also trans mittcd: by the antenna to a separate secondary circuit a tuned to the other wave length to which the antenna is resonant. The secondary circuits 3 and 4 comprise deblock condensers 7 and 8 in the respective circuits 3 and 4 in series opposition into a circuit including a telephone 9. As long as the antenna receives only atmospheric disturbances, the disturbances are completely eliminated, assuming that the detectors are connected in series opposition and possess identical characteristics for all occurring different intensities. If, however, signals are added to the disturbances, the signalling energy will be transmitted mainly to the circuit 3 and will, therefore, not be compensated. In addition to the signal, slight disturbances will be heard in the telephone 9, because the detectors 5 and 6 will be caused to operate at diiferent points of their characteristics. This is not objectionable at such time but rather is an advantage because it increases the audibility of the signal. However, during the intervals between signaling, complete freedom from disturbances may be attained in the-use of the invention.

The invention can be used to even greater advantage for the receiving of nndamped oscillations. A circuit arrangement for this purpose is illustrated in 2. The separation of the energies is accomplished e. g. by intermediate circuits 3 and i between the two-wave antenna 1 and the detector circuits 3 and 4c. The circuits 3 and 4 may be tuned correspondingly to the detector circuits 3 and 4, that is, to the wave length of the signals to be received and to the other wave length to which the antenna is tuned respectively. Both detector energies are conducted in opposition through the retardation coils lOand 11 to the common collecting condenser 12, and from there, in the case of telegraphy signals, through a normally operating tone producing interrupter 13 to the telephone 9. The purpose of the retardation coils 10 and 11 or similar suitable alternating current impedances is to prevent a mutual disturbance in the separate secondary high frequency circuits through the collecting condenser 12. There is again complete compensation of the disturbances occurring between signals, but during signalling, there is now also a n effect of the unneutralized disturbing energy which has also imparted to it a tone characteristic on the telephone or other indicator 9.

It will be understood from the foregoing thatin this compensating circuit arrangement, the intensity of the signals must be increased, for example, by the use of amplifying arrangements.

Preferably, the latter are employed in the detector circuit so as to improve the useful effect of the connection which is somewhat lessened due to the compensation of the disturbances.

Claims.

1. In combination, a plurality of detectors, means for impressing desired and undesired electrical energies on said detectors, an indicator, means for affecting said indicator by the energies rectified by said detectors in opposite sense, and means whereby said dotectors operate on the same portions of: their characteristics when only undesired energy is impressed thereon and said detectors operate on different portions of their characteristics when both undesired and desired energies are impressed thereon.

2. In combination, a plurality of detectors, means for impressing a signal frequency on one of said detectors and undesired electrical energy on said plurality of detectors, an indicator, means whereby the rectified energies from said detectors affect said indicator in opposite sense, means whereby said undesired energy is neutralized during a signalling interval but increases the effect of the signal frequency during a signalling period.

3. In combination, an indicating device, parallel paths arranged to affect said device, means for impressing desired and undesired electrical energies on said paths, and means whereby the effect of said undesired energy on said device is nil when no desired energy is impressed on said paths and said undesired energy augments the cifcct of the desired energy on said device when desired energy is impressed on said paths.

4-. In combination, a plurality of circuits each tuned to a different frequency, means for impressing desired and undesired frequencies on said circuits, a separate detector associated with each of said circuits, a con denser, means for impressing the frequencies rectified by said detectors on said condenser in opposite sense, said means including iin pedances, and indicator means connected across said condenser.

5. A receiving arrangement for wireless telegraphy and telephony comprising an antenna tuned to two wave lengths, one of which is the wave length of signalling energy to be received, secondary circuits loosely coupled with the antenna and tuned respectively to said wave lengths, detectors in the secondary circuits, a condenser with which the detectors are connected in series opposi tion, impedances interposed between the detectors and said condenser, a circuit includ ing said condenser and an indicator in the last-mentioned circuit.

In testimony whereof I aiiix the signature.

ALEXANDER MEISSNER. 

